Contents Of Re Research Articles

Solidification behavior of Re- and Ru-containing Ni-based single-crystal superalloys with thermal and metallographic analysis

To clarify the solidification behavior of Re- and Ru-containing Ni-based single-crystal superalloys, four experimental alloys with varied contents of Re and Ru were investigated by differential scanning calorimetry (DSC) and metallographic techniques. To obtain the γ′-solvus temperatures, the stepwise solution and aging heat treatments were used. DSC analysis shows that Re leads to the increase in freezing range and γ′-solvus temperature. On the contrast, Ru only has negligible influence on the freezing range, but leads to the lower γ′-solvus temperature. In comparison with Ru, Re leads to more severe segregation and higher eutectic fractions in as-cast microstructures. Furthermore, the castability and phase stability of Ni-based superalloys were analyzed by the results of DSC and metallographic analysis, such as freezing range, critical nucleation temperature, γ′-solvus temperature and eutectic fractions. It shows that Re leads to the wider freezing range and lower critical nucleation temperature, indicating the worse castability of Re-containing Ni-based single-crystal superalloys. The characteristic phase transformation temperatures of Re-containing single-crystal superalloy are determined by DSC analysis. For as-cast samples, the liquidus, solidus, critical nucleation and eutectic reaction temperature are clearly shown in DSC curves. After a stepwise solution and aging heat treatments, the higher amount of γ′ phase with cubic morphology can be obtained. Finally, the precipitation temperature of γ′ phase is determined by DSC analysis for the heat-treated samples.

The influence of melt flux and crustal processing on Re–Os isotope systematics of ocean island basalts: Constraints from Galápagos

New rhenium–osmium data for high-MgO (>9 wt.%) basalts from the Galápagos Archipelago reveal a large variation in 187Os/188Os (0.1304 to 0.173), comparable with the range shown by primitive global ocean island basalts (OIBs). Basalts with the least radiogenic 187Os/188Os occur closest to the Galápagos plume stem: those in western Galápagos have low 187Os/188Os, moderate 87Sr/86Sr, 143Nd/144Nd, 206Pb/204Pb and high 3He/4He whereas basalts in the south also have low 187Os/188Os but more radiogenic 87Sr/86Sr, 143Nd/144Nd, 206Pb/204Pb and 3He/4He. Our new Os isotope data are consistent with the previously established spatial zonation of the common global isotopic mantle reservoir “C” and ancient recycled oceanic crust in the mantle plume beneath western and southern parts of Galápagos, respectively.Galápagos basalts with the most radiogenic 187Os/188Os (up to 0.1875) typically have moderate MgO (7–9 wt.%) and low Os (<50 pg g−1) but have contrastingly unenriched Sr, Nd and Pb isotope signatures. We interpret this decoupling of chalcophile and lithophile isotopic systems as due to assimilation of young Pacific lower crust during crystal fractionation. Mixing models show the assimilated crust must have higher contents of Re and Os, and more radiogenic 187Os/188Os (0.32), than previously proposed for oceanic gabbros. We suggest the inferred, exceptionally-high radiogenic 187Os of the Pacific crust may be localised and due to sulfides precipitated from hydrothermal systems established at the Galápagos Spreading Centre.High 187Os/188Os Galápagos basalts are found where plume material is being dispersed laterally away from the plume stem to the adjacent spreading centre (i.e. in central and NE parts of the archipelago). The extent to which crustal processing influences 187Os/188Os appears to be primarily controlled by melt flux: as distance from the stem of the Galápagos plume increases, the melt flux decreases and crustal assimilation becomes proportionally greater, accounting for co-variations in Os and 187Os/188Os. The Os concentration threshold below which the 187Os/188Os of Galápagos basalts are contaminated (100 pg g−1) is higher than the canonical value (<50 pg g−1) assumed for many other global OIBs (e.g. for Iceland, Grande Comore and Hawaii). This most likely reflects the low overall melt flux to the crust from the Galápagos plume, which has only a moderate excess temperature and buoyancy flux. Our findings have implications for the interpretation of 187Os/188Os ratios in other ocean island settings, especially those where large variations in 187Os/188Os have been linked to heterogeneity in mantle lithology or sulfide populations: the effect of crustal contamination on 187Os/188Os may be greater than previously recognised, particularly for basalts associated with weak, low melt flux mantle plumes, such as Tristan, Bouvet, Crozet and St Helena.

Variation of Ginsenosides in Ginseng of Different Ages

Panax ginseng has been used in traditional oriental medicine for thousands of years. Ginsenosides, the major chemical components of the roots, are considered to be responsible for the medicinal properties of ginseng. Ginsenosides increase with the age of ginseng root in general knowledge, and in this study the content of ginsenosides in ginseng of different ages was quantified. Separation and determination of eight main ginsenosides, Rg1, Re, Rb1, Rc, Rg2, Rb2, Rb3 and Rd, was performed by high performance liquid chromatography with UV detection at 203 nm. The content of Rg1, Re, Rb1, Rc, Rg2 and Rd increased from 5 to 16-year-old ginseng and then decreased, while Rb2 and Rb3 increased in the range of 5-12 years, but then slowly decreased. However, the total eight ginsenosides in 16 year old ginseng had a higher content than that in any other from 5-18 years old. As a result, the content of ginsenosides and total ginsenosides was not positively related to age from 5-18 years, which is not in full agreement with the general knowledge of ginseng. Thus, this study suggests that the older wild ginseng may not result in better medicinal ginseng for herbal medicines.

Effects of RE on Precipitation Behaviors of the Inclusions and Magnetic Properties of Non-Oriented Electrical Steel

Effects of RE addition on deoxidation and desulphurization efficiency, precipitation behaviors of the inclusions, microstructure and magnetic properties of the finished sheets have been investigated for no-oriented electrical steel produced in industrial scale. The most suitable addition amount of RE alloy added in the electrical steel bearing is proposed for excellent deoxidation and desulphurization efficiency. RE added into the steel can form larger and higher melt point RE oxides, RE sulfides and RE oxysulfides inclusions removing from the bath by floating which decreases the numbers and increases the size of the fine inclusions. The average size of the inclusions remained in the steel is 0.8μm~1.4μm. RE content affects grain size by influencing number and size of fine inclusions in the finished steel sheets. The magnetic flux density of the finished steel sheets dereases with the increase of RE content while the lowest core loss of it has an optimum RE content in the steel. In the steel bearing 1.15wt% Si, the content of RE should be strictly controlled in the range from 20×10-4 wt% to 60×10-4 wt%.

Doping induced structural transformation in tungsten trioxide

Effects of dopants on structural stability of monoclinic WO3 were studied using density functional theory. Transformation from monoclinic to cubic crystal structures was obtained by gradually increasing doping concentrations of both rhenium (Re) and electrons inside the monoclinic WO3, whereas a large distortion of WO6 octahedra was observed by gradually increasing doping concentrations of both niobium (Nb) and holes inside the monoclinic WO3. It was verified that RexW1-xO3 has a cubic structure if x is larger than 0.375, and the transformation from monoclinic to cubic structure is mainly dependent on the occupancy of the W 5d orbital. The elastic characteristics of the RexW1-xO3 decrease with the increase of the content of Re in the range of 0.375 ≤ x ≤ 0.875.

Determination of platinum-group elements in rocks by ICP-MS with external calibration after cation exchange separation of matrix elements by KU-2-8 resin

The analytical technique to determine platinum-group elements ( PGEs ) Ru, Rh, Pd, Ir, Pt and Re in the geological samples within 0.1 ng/g – 10 μg/g range and Os on ng/g level in the ultramafic rocks by inductively coupled plasma mass-spectrometry with external calibration and without chemical removal of main interferences of Zr and Hf was proposed. The samples were prepared after their burning by acid decomposition in the open vessels, melting the insoluble residue with NH 4 F and with a subsequent cation exchange separation of PGEs from matrix elements by KU-2-8 resin (Russia). The measurements have been carried out using the high resolution mass-spectrometer Element 2 (Germany). The accuracy of the technique on μg/g level has been verified with reference materials: pyrrhotite ore RP-1 (Russia) and sulfide copper-nickel ore Zh-3 (Russia). In addition, the accuracy of the trace level (ng/g) has been verified by comparison of the results obtained in this study with those reported in the literature for international sample of comparison OPY-1, developed by the International Association of Geoanalysts (IAG). The procedural blanks are 0.000 n ng/ml for Os, 0.00 n ng/ml for Ru, Rh, Re, Ir and 0.0 n ng/ml for Pt and Pd. The detection limits were estimated by taking into account the blanks and their standard deviations (sample mass 1 g, volume 50 ml) and were 0.02 ng/g for Os, 0.07 ng/g for Re, 0.09 ng/g for Rh and Ir, 0.13 ng/g for Ru, 1.0 ng/g for Pt and 1.4 ng/g for Pd respectively. The content of Re was determined in the reference materials RP-1 and Zh-3, and in the sample of comparison OPY-1. Key words : platinum-group elements and Re, inductively coupled plasma mass-spectrometry, chromatographic separation, RP-1, Zh-3, OPY-1, external calibration. (Russian) DOI: http://dx.doi.org/10.15826/analitika.2016.20.3.003 V.I. Men’shikov, V.N. Vlasova, V.I. Lozhkin, Iu.V. Sokol’nikova Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences (IGC SB RAS) Favorsky ul., 1A, Irkutsk, 664033, Russian Federation

Elemental settling and burial fluxes in the Cariaco Basin

The vertical flux of particles and their interactions within the ocean, together with the global ocean circulation, control the water-column distribution of a wide range of elements. Such processes condition patterns of their deposition and burial within marine sediments. Our understanding of these processes can be used to hindcast environmental conditions in the past from the sedimentary record. Here we report the major, minor and trace element compositions of a small sub-set of samples of sinking material collected at four depths (225, 410, 810, 1200m) in the Cariaco Basin (10.5° N, 64.67° W), which is anoxic below ~275m depth. We compare these data with the composition of the most recent basin floor sediment at the same location. The sediment trap samples examined represent material collected during both a high- and a low-productivity season, during a short-period flood event in coastal Venezuela, and immediately following an earthquake that induced a gravity flow. Our results show that the lithogenous composition of all four groups of trap samples and the basin floor sediment is uniform. This indicates that the source of siliciclastic detritus is largely from the local rivers draining the coastal region to the south of the Cariaco station. Enrichments of Ba relative to a model lithogenous background are found in the opal-rich high productivity samples from all depths; enrichments of Ag, Cd, Cu, Ni and Zn, directly associated with the flux of phytoplankton organic matter from the photic zone, are found not only in the high productivity samples, but also in the low productivity samples that have higher CaCO3 contents and lower organic matter and opal contents. In addition, modest particle and sediment enrichments of some redox-sensitive trace elements that are known to be removed from solution and sequestered in suboxic and anoxic sediments, namely Cr, V and Re are observed. However, barely detectable enrichments of U and Mo are present in all trap samples. In contrast with the trap sample compositions, the modern laminated basin-floor sediment exhibits significantly higher contents of Re, Mo and U than a solely lithogenous contribution, confirming studies that have found greater sub-sea floor fixation of these elements. Finally, the high settling flux of Ba observed in the high productivity trap samples is not preserved in the bottom sediment.

Effect of salicylic acid on photosynthesis,physio-biochemistry and quality of Panax ginseng under full sun shine in spring

In order to search for a new pathway to improve the yield of ginseng through growing at the full sun shine accompanied by salicylic acid (SA), the net photosynthetic rate (P(n)), superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), malondialdehyde (MDA) in Panax ginseng leaves, and the content of ginsenosides in roots were compared under various concentrations of SA and full sun shine with the traditional shade shed. Under the full sun shine, 0.05, 0.2 mmol x L(-1) SA increased net photosynthetic rate to a great extent. Under the cloudy day, the average net photosynthetic rate increased by 127.8% and 155.0% over the traditional shade shed, 13.9% and 27.5% over the treatment without SA respectively; under the clear day, 23.5% and 30.4% over the traditional shade shed, 8.6% and 14.6% over the treatment without SA, particularly obvious in the morning and late afternoon. With such concentration, SA increased activities of SOD, CAT, POD, and decreased the contents of the MDA. This difference resulted from different light intensity, rise of light saturation point, and fall of compensation point. Full sun shine decreased ginsenosides contents, but with SA, the ginsenosides regained, the content of Rg1 and Re, Rb1, total six types of ginsenosides in SA 0.2 mmol x L(-1) group were higher than those in the control group (P < 0.05) and other groups. The application of 0.2 mmol x L(-1) SA under full sun shine during a short time has little threat to the P. ginseng in spring, and could enhance the resistance to the adversity, which would improve the yield of ginseng heavily.

An overview of rhenium effect in single-crystal superalloys

Nickel-based single-crystal superalloys are the key materials for the manufacturing and development of advanced aeroengines. Rhenium is a crucial alloying element in the advanced nickel-based single-crystal superalloys for its special strengthening effects. The addition of Re could effectively enhance the creep properties of the single-crystal superalloys; thus, the content of Re is considered as one of the characteristics in different-generation single-crystal superalloys. Owing to the fundamental importance of rhenium to nickel-based single-crystal superalloys, much progress has been made on understanding of the effect of rhenium in the single-crystal superalloys. While the effect of Re doping on the nickel-based superalloys is well documented, the origins of the so-called rhenium effect are still under debate. In this paper, the effect of Re doping on the single-crystal superalloys and progress in understanding the rhenium effect are reviewed. The characteristics of the d-states occupancy in the electronic structure of Re make it the slowest diffusion elements in the single-crystal superalloys, which is undoubtedly responsible for the rhenium effect, while the postulates of Re cluster and the enrichment of Re at the γ/γ′ interface are still under debate, and the synergistic action of Re with other alloying elements should be further studied. Additionally, the interaction of Re with interfacial dislocations seems to be a promising explanation for the rhenium effect. Finally, the addition of Ru could help suppress topologically close-packed (TCP) phase formation and strengthen the Re doping single-crystal superalloys. Understanding the mechanism of rhenium effect will be beneficial for the effective utilization of Re and the design of low-cost single-crystal superalloys.

Traditional Chinese medicine pairs(Ⅲ)—effect of extract of Ginseng Radix et Rhizoma and Puerariae Lobatae Radix on intestinal absorption in rats

This study focused on the intestinal absorption of traditional Chinese medicines (TCM) to reveal the scientific connotation of the compatibility of TCM pairs. The single pass intestinal perfusion (SPIP) was used in rats to compare the absorption of single extracts from Puerariae Lobatae Radix, single extracts from Ginseng Radix et Rhizoma, combined extracts from Puerariae Lobatae Radix and Ginseng Radix et Rhizoma and Puerariae Lobatae Radix and Ginseng Radix et Rhizoma mixture in rats. The content of puerarin, ginsenoside Rg1, ginsenoside Re and ginsenoside Rb1 in liquid were tested by HPLC. The speed constant (Ka) and apparent permeability coefficients (Papp) were calculated and compared. Specifically, the order of puerarin Ka and Papp values from high to low was Ginseng Radix et Rhizoma and Puerariae Lobatae Radix mixture > single extracts from Puerariae Lobatae Radix > combined extracts from Ginseng Radix et Rhizoma and Puerariae Lobatae Radix; the order of ginsenosides Ka and Papp values from high to low was Ginseng Radix et Rhizoma and Puerariae Lobatae Radix mixture > single extracts from Ginseng Radix et Rhizoma > combined extracts from Ginseng Radix et Rhizoma and Puerariae Lobatae Radix. The combined administration of Ginseng Radix et Rhizoma and Puerariae Lobatae Radix may improve the absorption in the intestinal tract.

Increase in apoptotic effect of Panax ginseng by microwave processing in human prostate cancer cells: in vitro and in vivo studies

BackgroundGinseng, which is widely used in functional foods and as an herbal medicine, has been reported to reduce the proliferation of prostate cancer cells by mechanisms that are not yet fully understood. MethodsThis study was designed to investigate the changes in ginsenoside content in ginseng after treatment with a microwave-irradiation thermal process and to verify the anticancer effects of the extracts. To confirm the anticancer effect of microwave-irradiated processed ginseng (MG), it was tested in three human prostate cancer cell lines (DU145, LNCaP, and PC-3 cells). Involvements of apoptosis and autophagy were assessed using Western blotting. ResultsAfter microwave treatment, the content of ginsenosides Rg1, Re, Rb1, Rc, Rb2, and Rd in the extracts decreased, whereas the content of ginsenosides 20(S)-Rg3, 20(R)-Rg3, Rk1, and Rg5 increased. Antiproliferation results for the human cancer cell lines treated with ginseng extracts indicate that PC-3 cells treated with MG showed the highest activity with an half maximal inhibitory concentration of 48 μg/mL. We also showed that MG suppresses the growth of human prostate cancer cell xenografts in athymic nude mice as an in vivo model. This growth suppression by MG is associated with the inductions of cell death and autophagy. ConclusionTherefore, heat processing by microwave irradiation is a useful method to enhance the anticancer effect of ginseng by increasing the content of ginsenosides Rg3, Rg5, and Rk1.

Re–Os dating of sulphides from the Yushui Cu-polymetallic deposit in eastern Guangdong Province, South China

The Yushui Cu-polymetallic deposit, which is associated with Ag, Pb, and Zn, is located in the middle part of the Yongan–Meixian Late Paleozoic Hercynian depression. It was discovered in eastern Guangdong Province in the late 1980s and is one of the richest copper deposits in China with high-grade copper averaging 3.25% and locally reaching 50–60%. The main ore body is located along the unconformity between the Upper Carboniferous Hutian Group limestone and the Lower Carboniferous Zhongxin Formation quartz sandstone with a bedded and lenticular morphology. The ores exhibit massive textures dominated by chalcopyrite, bornite, chalcocite, pyrite, sphalerite, galena, and a trace amount of argentite. Although researchers began studying the Yushui deposit in the early 1990s, the ore genesis remains controversial because of the lack of precise mineralisation age constraints. In this study, direct Re–Os dating of Cu sulphides aided in facilitating a better understanding of the timing of formation of the Yushui deposit. This study is the first attempt to use the Re–Os isotopic system for directly dating chalcopyrite and bornite ores for the Yushui deposit. The contents of Re, common Os, 187Re and 187Os in nine sulphides are 1.68–219.35ppb, 0.003–0.427ppb, 1.05–137.31ppb, and 0.045–0.734ppb, respectively. The isotope data yielded an isochron age of 308±15Ma (mean square weighted deviates=2.4) using the 87Re/188Os–187Os/188Os plot, which is interpreted to represent the age of formation for these sulphides, suggesting that the mineralisation age of the Yushui deposit is close to the age of the host rocks. The 187Os/188Os initial value obtained from the Re–Os isochron is 1.81±0.34, which corresponds to the γOs value of +1349. This value indicates that the ore-forming materials were derived from the crust without mixing with materials from the mantle, and that the Yushui massive sulphide deposit may be of sedimentary exhalative origin.

Accumulation characteristics and correlation analysis of five ginsenosides with different cultivation ages from different regions

BackgroundGinseng (the roots of Panax ginseng Meyer) is a well-known traditional Oriental medicine and is now widely used as a health food. It contains several types of ginsenosides, which are considered the major active medicinal components of ginseng. It has recently been reported that the qualitative and quantitative properties of ginsenosides found in ginseng may differ, depending on cultivation regions, ages, species, and so on. Therefore, it is necessary to study these variations with respect to cultivation ages and regions. MethodsIn this study, 3–6-yr-old roots of P. ginseng were collected from three different cultivation regions. The contents of five ginsenosides (Rb1, Rd, Rc, Re, and Rgl) were measured by rapid resolution liquid chromatography coupled with quadruple–time-of-flight mass spectrometry. The Kruskal–Wallis Rank sum test and multiple t test were used for comparative analysis of the data to evaluate the dynamic changes in the accumulation of these ginsenosides affected by cultivation regions and ages. ResultsThe content and composition of ginsenosides varied significantly among specimens collected from different cultivation regions and having different cultivation ages. For all samples, the content of Rg1 and Re ginsenosides increases with age and this rate of increase is different for each sample. The contents of Rb1, Rc, and Rd varied with cultivation ages in samples from different cultivation regions; especially, Rb1 from a 6-yr-old root showed approximately twofold variation among the samples from three cultivation regions. Furthermore, the content of Rb1 highly correlated with that of Rd (r = 0.89 across all locations and ages). ConclusionIn our study, only the contents of ginsenosides Rg1 and Re were affected by the root age. Ginsenosides Rb1, Rc, and Rd varied widely with ages in samples from different cultivation regions.

Near-infrared reflectance spectroscopy (NIRS) for rapid determination of ginsenoside Rg1 and Re in Chinese patent medicine Naosaitong pill

Ginsenosides in plant samples have been extensively studied because protopanaxadiol saponins are ubiquitous in Chinese patent medicines, in which they can be used in promoting human health as the main active ingredients. A method for rapid determination of two ginsenosides (Rg1 and Re) in Naosaitong (NST) samples using near-infrared reflectance spectroscopy (NIRS) is studied to determine the contents of ginsenoside Rg1 and Re in this work. Partial least square (PLS) regression was used for building the calibration models, and the effects of spectral preprocessing and variable selection on the models are investigated for optimization of the models. A total of 93 samples were scanned by NIRS, and also by high performance liquid chromatography coupled to a diode array detector to determine the contents of ginsenoside Rg1 and Re. The calibration models for Rg1 and Re had high values of the coefficient of determination (R2) (0.9766 and 0.9764) and low root mean square error of cross validation (RMSECV) (0.0136 and 0.0104), and the values of the standard error of prediction set (SEP) are 0.00764 and 0.0103, which indicate a good correlation between reference values and NIRS predicted values. The overall results show that NIRS could be applied for the rapid determination of the contents of ginsenosides in Ginseng byproducts for pharmaceuticals that develop high-quality Chinese patent medicines.

Influence of different processed methods on 10 kinds of ginsensides in Panacis Quinquefolii Radix

The influence on 10 kinds of ginsensides of different processed methods of Panacis Quinquefolii Radix was discussed. White Panacis Quinquefolii Radix (sliced and dried at -80 °C), red Panacis Quinquefolii Radix( steamed, sliced and dried at -80 °C) and commercial Radix Panacis Quinquefolii (dried by electric blast air) processed by different methods. HPLC-PDA-ESI- MS method was established before by our team. Ten kinds of ginsenosides of them were determined. The content of total ginsenosides were as follow: commercial Panacis Quinquefolii Radix > white Panacis Quinquefolii Radix > red Panacis Quinquefolii Radix. Compared with white Panacis Quinquefolii Radix, the content of Re, Rc, Rb3 and Rb2 of Red Radix Panacis Quinquefolii decreased but increased that of Rg,, Rb1. Both Rg2 and Rg, were not found in white Panacis Quinquefolii Radix and commercial Panacis Quinquefolii Radix by PDA detector, and low response in ESI-MS, while red Panacis Quinquefolii Radix was to the high content that of 0. 027% and 0.040 1%. The constituent of RA0 of red Panacis Quinquefolii Radix was higher than the other two. After Panacis Quinquefolii Radix processed, the kind and content of ginsensides were significantly changed. The constituent of some kinds of ginsensides was increased and some decreased. Rf was not found in all Panacis Quinquefolii Radix samples which were consistent with the former documents.

증숙 발효 공정에 의한 파삼의 진세노사이드 전환 수율 증진

This study was performed to enhance contents of low molecular ginsenoside using steaming and fermentationprocess in low quality fresh ginseng. For increase in contents of Rg2, Rg₃, Rh2 and CK in low quality fresh ginseng, a steamingprocess was applied at 90℃ for 12 hr which was followed by fermentation process at Lactobacillus rhamnosus HK-9incubated at 36℃ for 72 h. The contents of ginsenoside Rg1, Rb1, Rc, Re and Rd were decreased with the steaming associatedwith fermentation process but ginsenoside Rg2, Rg₃, Rh2 and CK increased after process. It was found that under thesteaming associated with fermentation process, low molecule ginsenosides such as Rg2, Rg₃, Rh2 and CK were increased as3.231 ㎎/g, 2.585 ㎎/g and 1.955 m/g and 2.478 ㎎/g, respectively. In addition, concentration of benzo[α]pyrene in extracts ofthe low quality fresh ginseng treated by the complex process was 0.11 ppm but it was 0.22 ppm when it was treated with thesteaming process. This result could be caused by that the most efficiently breakdown of 1,2-glucoside and 1,4-glucoside linkageto backbone of ginsenosides by steaming associated with fermentation process. This results indicate that steaming processand fermenration process can increase in contents of Rg2, Rg₃, Rh2 and CK in low quality fresh ginseng.

Influence of W-phase on mechanical properties and damping capacity of Mg–Zn–Y–Nd–Zr alloys

This work mainly investigated the influence of W-phase on the mechanical properties and damping capacities of as-cast Mg–Zn–Y–Nd–Zr alloys with Zn/RE (rare element) ratio about 1.0. Obtained results indicate that the alloys with Zn and RE addition are composed of α-Mg matrix and W-phase. With the contents of Zn and RE increasing, the diffraction peaks of W-phase are gradually intensified and the morphology of W-phase transforms from fine-network microstructure to coarse-network microstructure. The tensile strength and fracture mechanism are strongly dependent on the quality of W-phase and the alloy with W-phase content of 8.0% has the highest strength as a result of strong atomic bonding between the W-phase and the Mg matrix. The damping capacities of Mg–Zn–Y–Nd–Zr alloys decrease gradually with the increasing amount of W-phase and then maintain at high level at high strain amplitude. The decline of damping capacity can be explained by the forming of W-phase, which makes more phases and interfaces form in the alloys. And the mobile dislocation densities in the alloys increase as residual stress at the interface of W-phase/Mg matrix and long dislocations generate in the α-Mg matrix. Therefore, the damping of alloy with high W-phase content improves accordingly with the increasing amount of moving dislocations.

Quality evaluation of American ginseng using UPLC coupled with multivariate analysis

An ultra performance liquid chromatography (UPLC)method combined with multivariate data analysis was developed to evaluate the quality of American ginseng by simultaneously determining the concentrations of six ginsenosides (Rg₁, Re, Rb₁, Rc, Ro and Rd)in the samples. For UPLC, acetonitrile with 0.01% formic acid and water with 0.01% formic acid were used as the mobile phase with gradient elution. Under the established chromatographic conditions, the six ginsenosides could be well separated and the results of linearity, stability, precision, repeatability, and recovery rate all reached the requirement of quantification analysis, respectively. The total contents of Rg₁, Re, and Rb₁ in 57 samples all reached the requirement of the 2015 edition of Chinese Pharmacopoeia. At the same time, the experimental data were analyzed by principle component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The crude drugs and the decoction pieces can be discriminated by a PCA method and the samples with different age can be distinguished by a PLS-DA method.

파종 방법에 따른 고려인삼의 대사체 비교

*Department of Medicinal Crop Research, NIHHS, Rural Development Administration, Eumseong 369-873, Korea.**Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.***College of Pharmacy, Chung-Ang University, Seoul 156-756, Korea.****Department of Food Science and Technology, Oregon State University, Corvallis, OR 97330, USA.ABSTRACT : Ginsenosides of roots in Panax ginseng were analyzed by metabolic-targeting HPLC using the partial leastsquares discriminant analysis (PLS-DA) and compared depending on sowing methods between direct seeding andtransplanting method. Score plots derived from PLS-DA could identify the sowing method between the direct seeding andtransplanting method in P. ginseng roots. The ginsenoside compounds were assigned as Rg1, Re, Rf, Rg2, Rb1, Rc,Rb2, Rb3, and Rd. Contents of Re, Rf, Rg2, Rb1, Rc, Rb3, and Rd of main roots produced from the transplanting methodwere relatively higher than those of samples produced from direct seeding method. Also, contents of Rg1, Re, Rf, Rg2, Rb1,Rc, Rb2, Rb3, and Rd of lateral roots from the transplanted samples were relatively higher than those of samples producedfrom direct seeding method. Therefore, HPLC with PLS-DA analysis can be a straightforward tool for identificationof ginsenosides in main or lateral roots of P. ginseng obtained from two different seeding methods between directand transplanting methods.Key Words : Panax ginseng Root, Sowing Method, Metabolic Targeting, HPLC

Stereospecific anticancer effects of ginsenoside Rg3 epimers isolated from heat-processed American ginseng on human gastric cancer cell

BackgroundResearch has been conducted with regard to the development of methods for improving the pharmaceutical effect of ginseng by conversion of ginsenosides, which are the major active components of ginseng, via high temperature or high-pressure processing. MethodsThe present study sought to investigate the anticancer effect of heat-processed American ginseng (HAG) in human gastric cancer AGS cells with a focus on assessing the role of apoptosis as an important mechanistic element in its anticancer actions. Results and ConclusionHAG significantly reduced the cancer cell proliferation, and the contents of ginsenosides Rb1 and Re were markedly decreased, whereas the peaks of less-polar ginsenosides [20(S,R)-Rg3, Rk1, and Rg5] were newly detected. Based on the activity-guided fractionation of HAG, ginsenoside 20(S)-Rg3 played a key role in inducing apoptosis in human gastric cancer AGS cells, and it was generated mainly from ginsenoside Rb1. Ginsenoside 20(S)-Rg3 induced apoptosis through activation of caspase-3, caspase-8, and caspase-9, as well as regulation of Bcl-2 and Bax expression. Taken together, these findings suggest that heat-processing serves as an increase in the antitumor activity of American ginseng in AGS cells, and ginsenoside 20(S)-Rg3, the active component produced by heat-processing, induces the activation of caspase-3, caspase-8, and caspase-9, which contributes to the apoptotic cell death.